Consultants working on California's high-speed rail programme billed taxpayers for a private plane, tiki bars and cigar lounges, according to a Fox Business report examining expense claims tied to the state's flagship infrastructure project.

The allegations strike at a programme that has long depended on outside contractors. The California High-Speed Rail Authority, the state agency overseeing the project, has relied heavily on consulting firms to manage design, engineering and programme controls for the line under construction in the Central Valley — a reliance that critics in the state legislature have questioned for years on cost grounds.

According to the report, the expense claims in question include charges for private air travel and visits to tiki bars and cigar lounges, submitted as billable costs under consultancy contracts paid with public funds. The items were identified in a review of spending on the project.

The authority has not yet publicly detailed which firms submitted the claims, the total value of the disputed expenses, or whether any amounts have been repaid. Fox Business did not report a figure for the overall value of the questioned charges.

For a project already under intense fiscal scrutiny, the disclosure adds a new dimension to the debate over its management. The California high-speed rail programme, intended to link San Francisco and Los Angeles with trains running at speeds of up to 350 km/h, has faced repeated cost overruns and schedule slippage since voters approved nearly $10 billion in bonds for it in 2008. Current estimates place the full build-out far above early projections, and the authority has focused first on a Central Valley segment between Merced and Bakersfield.

Expense-claim controversies carry particular weight for a public agency that must return to lawmakers and federal partners for continued funding. Governor Gavin Newsom's administration and the state legislature have sparred over allocations in recent budget cycles, and federal support has fluctuated with changes in Washington.

Consultancy spending is a significant line item in the project's budget. Outside firms have performed much of the day-to-day programme management, engineering and environmental work, with the authority maintaining a comparatively small in-house staff. That structure has drawn criticism from the state's own watchdogs, who have argued the agency lacks the internal capacity to police invoices effectively.

The question now is whether the disputed expenses trigger clawbacks, contract terminations or new oversight requirements. Similar findings in other US infrastructure programmes have historically led to audits by the state controller or the inspector general, and to reimbursement demands where charges failed contract terms.

Watchdogs and legislators are likely to press the authority for a full accounting of the claims, the contracting firms involved, and any disciplinary or financial recovery action already under way.